Local (external storage) folder is empty

My Setup is a Nextcloudpi at v15. I added a external storage as admin with no other options enabled.
I set up the Backup folder in the Webpanel to sync to this folder. After not seeing the backup folder in the Cloud (Webapp) I did following:

chmod -R 777 /media/myharddrive/nc-backups-autosync

to change the permissions. I also made a Data scan for external files and restore permissions (in Web panel)

I can see the backup file in the folder when i navigate to the folder via terminal (ssh).

Anyone an Idea how to make the backup file visile in the browser application?
(sho invisible files is already activated)